ORLANDO – Radiofrequency (RF) ablation is a safe and effective procedure for treating focal adrenal tumors in patients who are poor surgical candidates or who refuse adrenalectomy. With a short treatment time and minimal hospital stay, RF ablation can provide rapid clinical and biochemical improvement.
Dr. Lima Lawrence, an internal medicine resident at the University of Illinois at Chicago/Advocate Christ Medical Center in Oak Lawn, presented a case report and a review of the literature during an oral abstract session at the annual meeting of the American Association of Clinical Endocrinologists. The patient was a 65-year-old woman who presented with weight gain, decreased energy, and muscle weakness. On physical exam, she was hypertensive, anxious, obese, and had prominent supraclavicular fat pads. Salivary cortisol and overnight dexamethasone suppression tests were both elevated, and ACTH levels were depressed, confirming the diagnosis of a cortisol-secreting tumor causing adrenal Cushing’s syndrome. Computed tomography (CT) surveillance showed a progressively enlarging right-sided adrenal mass. A peritoneal biopsy revealed a low-grade serous neoplasm of peritoneal origin.
Her medical history included type 2 diabetes, uncontrolled hypertension, mixed connective tissue disease, depression, and total abdominal hysterectomy with bilateral salpingo-oophorectomy for ovarian cancer.
Dr. Lawrence said the patient had been scheduled for adrenalectomy, but it was not performed because of an intraoperative finding of peritoneal studding from what turned out to be metastatic ovarian cancer. Therefore, she underwent CT-guided RF ablation of the adrenal mass using a 14-gauge probe that heated a 3.5-cm ablation zone to 50-60 C for 8-10 minutes to achieve complete tumor necrosis.
The patient showed dramatic “clinical and biochemical improvement,” Dr. Lawrence said. The patient had no procedural complications and no blood loss and was observed for 23 hours before being discharged to home. A CT scan 8 weeks later showed a slightly decreased mass with marked decreased radiographic attenuation post-contrast from 30.2 Hounsfield Units (HU) preoperatively to 17 HU on follow-up.
Dr. Lima Lawrence
Potential adverse outcomes using RF ablation include a risk of pneumothorax, hemothorax, and tumor seeding along the catheter track, but this last possibility can be mitigated by continuing to heat the RF probe as it is withdrawn.
Published evidence supports use of RF ablation. “To date there have been no randomized clinical trials comparing the safety, efficacy, and survival benefits of adrenalectomy vs. radio frequency ablation,” she said. It may not be feasible to do a randomized trial. But a review of the literature generally supports the efficacy of the technique although the publications each involved a small series of patients, Dr. Lawrence said in an interview.
A 2003 series (Cancer. 2003;97:554-60) of 15 primary or metastatic adrenal cell carcinomas that were unresectable or were in patients who were not surgical candidates showed nonenhancement and no growth in 8 (53%) at a mean follow-up of 10.3 months. Eight of the 12 tumors of 5 cm or smaller had complete loss of radiographic enhancement and a decrease in size.
From a retrospective series of 13 patients with functional adrenal neoplasms over 7 years, there was 100% resolution of biochemical abnormalities and clinical symptoms at a mean follow-up of 21.2 months. One small pneumothorax and one limited hemothorax occurred, neither of which required hospital admission. There were two instances of transient, self-remitting hypertension associated with the procedures (Radiology. 2011;258:308-16).
In 2015, one group of investigators followed 11 patients for 12 weeks postprocedure. Eight of nine patients with Conn’s syndrome attained normal serum aldosterone levels. One with a nodule close to the inferior vena cava had incomplete ablation. Two of two Cushing’s patients had normal cortisol levels after the procedure (J Vasc Interv Radiol. 2015;26:1459-64).
A retrospective analysis of 16 adrenal metastases showed that 13 (81%) had no local progression over 14 months after ablation. In two of three functional adrenal neoplasms, clinical and biochemical abnormalities resolved (Eur J Radiol. 2012.81:1717-23).
A retrospective series of 10 adrenal metastases showed that one recurred at 7 months after image-guided thermal ablation, with no recurrence of the rest at 26.6 months. There was no tumor recurrence for any of the cases of metastatic disease localized to the RF ablation site (J Vasc Interv Radiol. 2014;25:593-8).
Results were somewhat less good in a retrospective evaluation of 35 patients with unresectable adrenal masses over 9 years. Although 33 of 35 (94%) lost tumor enhancement after the initial adrenal RF ablation, there was local tumor progression in 8 of 35 (23%) patients at a mean follow-up of 30.1 months (Radiology. 2015;277:584-93).
Finally, Dr. Lawrence discussed a systematic literature review on adrenalectomy vs. stereotactic ablative body radiotherapy (SABR) and percutaneous catheter ablation (PCA) in the treatment of adrenal metastases: 30 papers on adrenalectomy on 818 patients; 9 papers on SABR on 178 patients; and 6 papers on PCA, including RF ablation, on 51 patients. The authors concluded that there was “insufficient evidence to determine the best local treatment modality for isolated or limited adrenal metastases.” Adrenalectomy appeared to be a reasonable treatment for suitable patients. SABR was a valid alternative for nonsurgical candidates, but they did not recommend PCA until more long-term outcomes were available (Cancer Treat Rev. 2014;40:838-46).